[Andy Reed]

Hi Greg

Good question. My gut feeling here would be to use your average power over the full 30 mins. If you divide that value by 1.02 then I think the difference that it makes is largely negligible as to make any meaningful difference. For example if your average power is 300W, then using Markus’ math would only change it to 294W, and as you will no doubt have experienced, power bounces all over the place if you follow it real time, when off-road. I think that 6W difference is really not going to make a big difference to how you train, especially on trails. And remember that watches are not even directly measuring power, it’s all math and algorithms, and there is no real consensus as to the most accurate algorithm, and different brands use their own proprietary methods. Given the inherent problems in determining power, I really don’t think that the correction factor is going to affect much in reality. As with anything though, the best thing is to maintain a consistent approach. Use the same approach whenever you repeat a test – make it as repeatable as possible, and if you do apply a correction factor, be consistent. Hope that helps.